EDINBURGH SCIENTISTS have made an important step in understanding how superbugs such as MRSA become resistant to antibiotic treatment.

In experiments that focused on E. coli, researchers from the University of Edinburgh have mapped the molecular structure of an enzyme found in many species of bacteria.

This enzyme protects against attack by other bacteria species or viruses. In a similar way, they allow bacteria to acquire resistance to antibiotics.

The success in mapping these enzymes is the first step in manipulating bacteria to slow or stop the absorption of DNA that may hold antibiotic resistance instructions.

Long-term exposure to antibiotics can lead to bacteria developing defences to block the effects of the drug. These defences are then passed into the genes of bacteria, which can spread quickly through bacterial populations through absorption between species.

Dr David Dryden of the university’s School of Chemistry said, “we have known for some time that these enzymes are very effective in protecting bacteria from attack by other species.

“Now we have painted a picture of how this occurs, which should prove to be a valuable insight in tackling the spread of antibiotic-resistant superbugs.”

MRSA is the most famous example of a superbug: a bacteria that has developed resistance to antibiotics such as penicillin. Their resistance does not make them more virulent than strains of MRSA that do not have resistance, but because they are difficult to treat they become more dangerous.

Oliver Blatchford, consultant in public health medicine at NHS Health Protection Scotland, told The Scotsman, “the NHS in Scotland has seen a steady reduction in the numbers of MRSA bloodstream infections.

“In the last reported quarter, July to September 2011, Scotland had 48 of these infections, which was the lowest number we have had since the start of the surveillance programme in 2005, when it was 221 MRSA bloodstream infections in a quarter.

“This reduction in MRSA bacteraemias [blood stream infections] has been the result of several different programmes aimed at improving the quality of healthcare services in Scotland.”